text: /***************************************************************************
   *                                  _   _ ____  _
   *  Project                     ___| | | |  _ \| |
   *                             / __| | | | |_) | |
   *                            | (__| |_| |  _ <| |___
   *                             \___|\___/|_| \_\_____|
   *
   * Copyright (C) 1998 - 2019, Daniel Stenberg, <daniel@haxx.se>, et al.
   *
   * This software is licensed as described in the file COPYING, which
   * you should have received as part of this distribution. The terms
   * are also available at https://curl.se/docs/copyright.html.
   *
   * You may opt to use, copy, modify, merge, publish, distribute and/or sell
   * copies of the Software, and permit persons to whom the Software is
   * furnished to do so, under the terms of the COPYING file.
   *
   * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
   * KIND, either express or implied.
   *
   ***************************************************************************/
  
  /* <DESC>
   * SMTP example showing how to expand an e-mail mailing list
   * </DESC>
   */
  
  #include <stdio.h>
  #include <string.h>
  #include <curl/curl.h>
  
  /* This is a simple example showing how to expand an e-mail mailing list.
   *
   * Notes:
   *
   * 1) This example requires libcurl 7.34.0 or above.
   * 2) Not all email servers support this command.
   */
  
  int main(void)
  {
    CURL *curl;
    CURLcode res;
    struct curl_slist *recipients = NULL;
  
    curl = curl_easy_init();
    if(curl) {
      /* This is the URL for your mailserver */
      curl_easy_setopt(curl, CURLOPT_URL, "smtp://mail.example.com");
  
      /* Note that the CURLOPT_MAIL_RCPT takes a list, not a char array  */
      recipients = curl_slist_append(recipients, "Friends");
      curl_easy_setopt(curl, CURLOPT_MAIL_RCPT, recipients);
  
      /* Set the EXPN command */
      curl_easy_setopt(curl, CURLOPT_CUSTOMREQUEST, "EXPN");
  
      /* Perform the custom request */
      res = curl_easy_perform(curl);
  
      /* Check for errors */
      if(res != CURLE_OK)
        fprintf(stderr, "curl_easy_perform() failed: %s\n",
                curl_easy_strerror(res));
  
      /* Free the list of recipients */
      curl_slist_free_all(recipients);
  
      /* Curl won't send the QUIT command until you call cleanup, so you should
       * be able to re-use this connection for additional requests. It may not be
       * a good idea to keep the connection open for a very long time though
       * (more than a few minutes may result in the server timing out the
       * connection) and you do want to clean up in the end.
       */
      curl_easy_cleanup(curl);
    }
  
    return 0;
  }
  